tbuckley/cabot-search huggingface dataset:
DDEL-02. LUMBAR OMMAYA RESERVOIR- A COST EFFECTIVE ALTERNATIVE TO INTRAVENTRICULAR OMMAYA RESERVOIR FOR TREATMENT OF LEPTOMENINGEAL DISEASE
Authors: Ivo Peo, Jay Kumar, Paul Krafft, Nam Tran
Journal: Neuro-Oncology (2022)

Abstract Introduction Lumbar puncture (LP) is a well-established approach for intrathecal (IT) delivery of chemotherapeutics for leptomeningeal disease (LMD). Intraventricular Ommaya reservoir (OR) has supplanted LPs as an easier and safer route for IT administration. Radiotherapy for treatment of LMD must be delayed in order for surgical wound healing following OR placement. Furthermore, prior cranial radiation can thin the scalp, predisposing to wound breakdown. Placement of lumbar Ommaya reservoir (LOR) provides an alternative to IT delivery, but this has not reached a wide-spread acceptance. Objective Provide cost-analysis and report patient outcomes after placement of LOR. METHODS Following IRB approval, all patients undergoing LOR placement between 2018 and 2020 were retrospectively reviewed. Patients age, primary tumor, survival lengths and complications were reviewed. Average procedure-related treatment cost was obtained from an uncomplicated representative case excluding the surgeon’s fee. RESULTS Fourteen patients (mean age 46.35 years) were identified. The mean follow-up was 440.7 (25-1003) days post-surgery. Acute lymphoblastic leukemia (n = 4), acute myeloblastic leukemia (n = 3), breast carcinoma (n = 3), ependymoma (n = 3), lymphoma (n = 2) and lung adenocarcinoma (n = 1) were identified as underlying malignancy. LMD was diagnosed on average after 581.1 days after the diagnosis of the underlying malignancy. 8 patients succumbed to their malignancy on average after 463.9 and 314.6 days after the diagnosis of LMD and LOR surgery, respectively. There were 2 complications – pain at the site of the LOR and a fractured catheter caused by inadvertent puncture of the catheter. No infections or wound healing complications were noted. Typical cost for placement of LOR and OR was – 17,350 USD and 29,052 USD, respectively. Placement of the LOR proved to be more cost-effective in this cohort by approximately 40% cost reduction. CONCLUSION Placement of LOR is a cost effective alternative to cranial OR with low complication profile, and well tolerated by patients.
NCMP-06. VENOUS THROMBOEMBOLISM INCIDENCE AND THE IMPACT OF PRE-DISEASED ANTICOAGULATION THERAPY IN GLIOBLASTOMA PATIENTS
Authors: Anthony Sloan, Theresa Elder, Ansh Desai, Anna Wu, Serah Choi, Andrew Sloan
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma (GBM) patients have a 24-30% risk of developing venous thromboembolism (VTE), including deep vein thrombosis or pulmonary embolism, over the course of their diagnosis. However, very little data exists regarding the impact of VTE on survival in GBM patients, with or without anticoagulation. This study aimed to investigate 1) the demographic factors associated with VTE incidence in GBM patients, 2) any correlation between VTE incidence and length of survival and, and 3) the impact of pre-diagnosis antiplatelet/anticoagulation therapy on VTE development and survival. A total of 150 GBM patients treated at University Hospital Seidman Cancer Center were included and retrospectively analyzed. Information was collected regarding history of aspirin, clopidogrel, DOAC, heparin, and/or warfarin use. The diagnosis of VTE both prior to GBM diagnosis and at various time points following diagnosis was determined followed by calculating overall survival and progression free survival (PFS). Of the 150 GBM patients, 53 (35.3%) developed a VTE overall. VTE incidence correlated with a lower KPS at presentation (r = -.225, p =.027) and a decrease in overall survival among GBM patients (r = -.191, p =.041). Antiplatelet/anticoagulation therapy prior to GBM diagnosis correlated with decreased VTE formation overall, as well as longer PFS among non-VTE patients (r =.261, p = .026) but not among patients who later developed VTE (r = .165, p = .302). Our findings demonstrate that patients with lower KPS are at a higher risk for developing VTE. Among GBM patients who did not develop VTEs, those on antiplatelet/anticoagulation therapy prior to diagnosis had longer PFS compared to those who were not on anticoagulants. These preliminary studies highlight the need for better VTE prophylaxis and therapy among GBM patients. These results further suggest the potential benefit of anticoagulation therapy in GBM patients irrespective of VTE formation.
MODL-37. DISCERNIBLE INTERINDIVIDUAL PATTERNS OF GLOBAL EFFICIENCY DECLINE DURING THEORETICAL BRAIN SURGERY
Authors: Lin Yueh-Hsin, Nicholas Dadario, Lewis Crawford, Onur Tanglay, Hsu-Kang Dow, Isabella Young, Syed Ali Ahsan, Stephane Doyen, Michael Sughrue
Journal: Neuro-Oncology (2022)

Abstract Resection of infiltrating brain tumors, such as diffuse gliomas, generally involves resecting a portion of a lobe of the brain. While the concept of localized functions, and the risk to removing these areas, is well established in neurosurgical thinking, the potential that the overall global efficiency of the connectome could be disproportionately disturbed by an intervention in ways which are not immediately obvious have not been formally studied. The current article provides evidence that structural patterns exist in the impact resection of various lobes of the brain has, which also differs between subjects. We utilized diffusion tractography to create structural connectivity graphs from the brains of 80 healthy adults, and then performed every plausible brain surgery in every gross anatomic region of the cerebrum by deleting every possible combination of nodes in the graph which were adjacent to each other, and measured the drop in global efficiency (GE) at each nodal deletion. Not surprisingly, the deletion of some nodes was worse than others, such that in every lobe we studied in every subject, there were combinations of deletions which were worse for GE than removing a greater number of nodes in a different part of the brain. Interestingly, while the worst nodes differed between subjects, there were specific nodes which typically showed up as particularly detrimental regardless of which node was the worst in that person, but that there were patterns of so-called ―connectotype, which could determine which nodes were the worst. Progressive removal of a lobe of the brain leads to patterns of global efficiency decline which are reasonably predictable, but which are not the same between subjects. Given evidence that global efficiency relates to specific neuro-cognitive abilities, this provides a path towards reducing the cognitive footprint of brain surgery.
EXTH-34. ANTI-RETROVIRAL REPURPOSING FOR TREATMENT OF GLIOBLASTOMA
Authors: Sarah Rivas, Vaidya Govindarajan, Mynor Mendez Valdez, John Heiss, Ashish Shah
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma (GBM) is a WHO grade IV glioma whose heterogeneous nature and stem-like features contribute to resistance to conventional chemotherapeutics. Previously, antiretrovirals have been proposed as anti-neoplastic agents, but their clinical efficacy is limited. With the advent of modern anti-retroviral and combinatorial therapy, we sought to repurpose FDA-approved anti-retroviral drugs for glioblastoma. Here, we performed an unbiased screen of 16 antiretrovirals in 40 glioma cell lines using DEPMap for drug repositioning. We identified six potential antiretrovirals among several drug classes with significant anti-glioma activity: abacavir (ABC), lamivudine (LMV), raltegravir (RLT), darunavir (DAR), indinavir (IND), and etravirine (ETV). We validated the effects of six antiretrovirals on patient-derived GBM neurospheres (GBM28 and GBM43) and established glioma cell line (A172). The non-nucleoside reverse transcriptase inhibitor (ETV) had the lowest effective IC50 in chemoresistant PDX GBM neurospheres (15uM) and A172 cells (2.7uM). Synergy assessment of ETV with standard of care temozolomide (TMZ) demonstrated that these drugs work independently of one another (Bliss score of -0.39 and -0.83 in GBM 28 and GBM 43, respectively). In addition, we investigated ETV effect on stemness features and human endogenous retroviral elements. Western blot, immunofluorescence and qPCR showed a decrease in the stemness markers, OCT-4, and HERV-K env expression. Reverse transcriptase levels decreased significantly after sublethal ETV treatment (5uM) for 48 hours in the stem-like GBMNS but not in adherent A172 cells. Overall, several antiretroviral drugs could be repositioned for glioblastoma therapy. Given its ideal therapeutic index and ability to penetrate the blood-brain barrier, ETV may be a promising candidate for future clinical trials in neuro-oncology.
TMIC-45. DISTRIBUTION AND TUMOR CELL PROXIMITY OF IMMUNE CELLS IN THE TUMOR CORE, INFILTRATION ZONE AND PERIPHERY OF GLIOBLASTOMAS
Authors: Vilde Pedersen, Arnon Møldrup Knudsen, Signe Regner Michaelsen, Bjarne Winther Kristensen
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma is the most frequent and malignant brain tumor. Immune therapies have had limited effect, but not much is known about the frequency and type of immune cells in the infiltration zone and periphery. In these areas, tumor cells migrate into the brain parenchyma and prevent total tumor resection thereby leading to recurrence. This study aims to quantify the type and distribution of immune cells in glioblastomas. A cohort of 67 glioblastomas was established containing tissue from central tumor and/or infiltration zone and/or tumor periphery. Patients were included if most tumor cells were positive in immunohistochemical staining for P53. A multiplex staining was established, where tissue sections were stained with P53 (tumor cells), FOXP3 (FOXP3+ regulatory T cells), CD8 (CD8+ cytotoxic T cells) and IBA1 (microglia/macrophages). Cells were counted in tumor core, infiltration zone and periphery using Visiopharm software based on training of convolutional neural networks. Moreover, the number of tumor cells with immune cells in proximity (30 µm) was quantified. The number of CD8+, FOXP3+ and Iba1+ cells was significantly higher in the core than in the periphery (P &amp;lt; 0.001), and in the infiltration zone than in the periphery (P &amp;lt; 0.001). However, the CD8+, FOXP3+ and Iba1+ cells/tumor cell ratio increased from core to infiltration zone and to periphery (P &amp;lt; 0.001). There was a higher amount of tumor cells with CD8+ cells in proximity in the tumor core (P &amp;lt; 0.001), whereas the highest amount of tumor cells with IBA1+ cells and FOXP3+ cells in proximity was the infiltration zone (P &amp;lt; 0.001). In conclusion, although levels of immune cells are highest in the tumor core - the higher proximity and ratio of immune cells to tumor cells in the infiltration zone/periphery suggest immune-suppressive mechanisms to be active in these areas.
MODL-12. A NOVEL GENETICALLY ENGINEERED H3.3G34R MODEL REVEALS COOPERATION WITH ATRX LOSS IN UPREGULATION OF HOXA CLUSTER GENES AND PROMOTION OF NEURONAL LINEAGE
Authors: Aalaa Abdallah, Herminio Cardona, Samantha Gadd, Daniel Brat, Nitin Wadhwani, Chen Shen, David Picketts, Xiao-Nan Li, Oren Becher
Journal: Neuro-Oncology (2022)

Abstract BACKGROUND Pediatric high-grade gliomas (pHGGs) are an aggressive CNS tumor which are often characterized by mutations in H3F3A, the gene that encodes Histone H3.3 (H3.3). A substitution of the Glycine at position 34 of H3.3 with either Arginine or Valine (H3.3G34R/V), was recently described in a large cohort of pHGG samples and has been characterized as occurring in anywhere between 5-20% of pHGGs. Attempts to study the mechanisms of H3.3G34R have proven difficult due to the developmental nature of the disease and the requirement of co-occurring mutations for model development. METHODS We utilized the RCAS/tv-a system to develop a genetically engineered mouse model (GEMM) that incorporates PDGF-A activation, TP53 loss and the H3.3G34R mutation both in the context of ATRX loss and ATRX presence in nestin expressing progenitor cells. RESULTS Transcriptomic analysis revealed that ATRX loss in the context of H3.3G34R upregulates the Hoxa cluster genes Hoxa2, Hoxa3, Hoxa5, and Hoxa7 (p &amp;lt; 0.05, unpaired t-test). H&amp;E staining and EMA immune-staining indicate that ATRX loss is correlated with a higher incidence of ependymal differentiation in H3.3G34R expressing samples (p &amp;lt; 0.05, unpaired t-test). GSEA and RT-qPCR analysis demonstrate that H3.3G34R expression in the context of ATRX loss promotes increased expression in genes associated with neuronal lineage (FWER pval &amp;lt; 1.0) and exhibits upregulation of the neurofilament polypeptides Nefl, Nefm (p &amp;lt; 0.05, unpaired t-test) as well as the neuronal differentiation marker Stmn2 (p &amp;lt; 0.001, unpaired t-test). CONCLUSION Our study proposes a model in which cooperation between ATRX loss and H3.3G34R expression mediate major transcriptomic and histopathological changes in H3.3G34R pHGGs. Broadly, our work highlights the importance to study mechanisms of co-occurring genetic events separately and in combination.
CSIG-35. TARGETING HYPOXIC CANCER CELLS IN MEDULLOBLASTOMA
Authors: Yuki Kuranaga, Erwin Van Meir
Journal: Neuro-Oncology (2022)

Abstract New treatment approaches are urgently needed for children with medulloblastoma (MB) to augment survival and reduce the long-term side effects from the treatment. Malignant tumors often display hypoxic regions where hypoxia-induced transcription factors (HIFs) increase the expression of genes that promote tumor growth (e.g., metabolic adaptation and invasion/metastasis). Based on the known roles of HIF in many solid tumors, we hypothesized that Hypoxia/HIFs contribute to MB cell growth and targeting HIF proteins is a viable strategy for treating MB. To test our hypothesis, first, we exposed MB cell lines (ONS-76; Shh and D556; Group 3) to 1% hypoxia in cell culture. We found increased expression of both HIF1a and HIF2a proteins and activation of a hypoxia-response element driven luciferase reporter assay. Treatment of the cells with 64B, an arylsulfonamide HIF inhibitor abrogated reporter activity and reduced expression of hypoxia-induced genes (GLUT-1, VEGF). Next, we used CRISPR/Cas9 to knockout singly or in combination HIF1a/HIF2a genes. The inhibition of HIF reporter activity by 64B was partially canceled in single HIF-KO cells and completely canceled in double HIFs-KO cells, showing both isoforms were active. Second, to investigate HIFs can be therapeutic targets, we established orthotopic human MB xenografts in mice. We first examined the tumor for the presence of hypoxic areas and used pimonidazole (Hypoxyprobe) injections followed by immunohistochemistry and found hypoxic areas throughout the tumors where tumor cells expressed HIF1a and/or HIF2a. Evaluation of human MB samples for HIF1/2 expression is also ongoing. Next, we plan on injecting mice with cells devoid of HIFs genes and examine their growth. We will also treat the mice with 64B to test whether it has anti-tumor effects and extends survival. In conclusion, these results indicate that HIF activation is part of the pathobiology of MB and HIF proteins may be a target for MB treatment.
TMIC-29. CHARACTERIZING THE ROLE OF TRIGGERING RECEPTOR EXPRESSED ON MYELOID CELLS 2 (TREM2)-EXPRESSING MICROGLIA/MACROPHAGES IN GLIOBLASTOMA
Authors: Mekenzie Peshoff, Pravesh Gupta, Shivangi Oberai, Nancy Milam, Aml Ahmed, Minghao Dang, Linghua Wang, Krishna Bhat
Journal: Neuro-Oncology (2022)

Abstract The tumor microenvironment in glioblastoma (GBM) contains numerous cell types, notably a rich immune compartment dominated by myeloid cells, such as brain-resident microglia and infiltrating macrophages. However, current immunotherapies target lymphoid components like T cells, which are sparse in the brain and the tumors originating there. Therefore, immune checkpoint drugs designed for systemic cancers have not yielded significant benefits for patients with glioblastoma, and the efficacy of immunotherapy for central nervous system malignancies lags behind treatments for other solid tumors. Further understanding of the myeloid compartment is necessary for developing glioblastoma immunotherapies. Our recent single cell RNA-seq (scRNA-seq) analyses have identified microglial clusters that are enriched for antigen presentation and phagocytic gene expression modules. These clusters were restricted to microglia and macrophages seen only in glioma patients, but not in myeloid cells derived from non-glioma brain controls. Triggering receptor expressed on myeloid cells 2 (TREM2), a receptor abundant on microglia and vital for the detection and phagocytosis of pathogens, was highly expressed in these clusters. Because microglia expressing TREM2 play a protective role in neurodegenerative diseases like Alzheimer's disease, we examined the function of TREM2+ myeloid cells in GBM using mice lacking TREM2. Implantation of GL261 cells in TREM2-/- mice showed significantly reduced survival relative to wild-type mice, suggesting a protective role of TREM2+ myeloid cells in glioma. Data on immunophenotyping of glioma xenografts from WT and TREM2-/- mice brains using state of the art technologies (e.g. Cytek) will be presented. We conclude that TREM2 is a phagocytic immunoregulator in glioblastoma, manifesting anti-glioma properties to TREM2+ myeloid cells.
MODL-09. MODELLING MIGRATION OF GLIOBLASTOMA PATIENT-DERIVED CELLS USING HUMAN IPSC-DERIVED NEURAL SPHEROID AND HIGH CONTENT IMAGING
Authors: Victoria Tsang, Davide Danovi, Ivo Lieberam
Journal: Neuro-Oncology (2022)

Abstract Glioblastoma multiforme (GBM) is the most common and aggressive brain tumour in adults. Despite current advances, the existing standard of treatment is ineffective, and the survival prognosis remains 18 months on average from diagnosis. Migrating tumour cells have been implicated in the therapeutic resistance of GBM. They spread by interacting with structures such as white matter tracts and inevitably cause recurrence of the tumour. Valuable cell models able to capture the invasiveness of GBM are critically needed to develop innovative therapies targeting migrating GBM cells. We established an in vitro model mimicking the GBM microenvironment by co-culturing patient-derived GBM cells and human-induced pluripotent stem cell-derived cortical neural spheroids with radiating axons. Using high content imaging, we developed a robust workflow to quantify the GBM cells' infiltration of the neural spheroid in endpoint assays. Images were acquired on the Operetta CLS and analysed using Harmony Imaging and Analysis Software. We also performed live imaging assays using the Phasefocus Livecyte, in which we studied the directionality, displacement and speed of the GBM cells engaged on axons. Our data indicate that GBM cells change morphology when cultured on axons and that they migrated towards the neural spheroid once engaged on axons. We showed that patient derived-cell lines representing different subtypes vary in migratory properties as well as in levels of infiltration capability. Finally, we used this model to test antagonists inhibiting pathways involved in the migration of GBM cells. To summarise, we developed a novel model able to mimic the GBM migration on axons and able to screen for compounds affecting cell migration which could potentially offer innovative precision-medicine therapies.
RADT-19. CHEMORADIATION (CRT) TREATMENT WITH OR WITHOUT CONCURRENT TUMOR-TREATING FIELDS (TTFIELDS) IN PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA (GBM)
Authors: Louis Cappelli, Allison Kayne, Peter Pan, James Cordova, Jiayi Huang, Tony Wang, Iyad Alnahhas, Wenyin Shi
Journal: Neuro-Oncology (2022)

Abstract OBJECTIVES Standard of care for newly diagnosed glioblastoma after resection includes concurrent temozolomide (TMZ) and radiation therapy followed by adjuvant TTF with maintenance TMZ. Preclinical studies suggest TTF and radiotherapy work synergistically. We evaluate the benefit of concurrent TTF with CRT vs adjuvant TTF with TMZ after CRT. METHODS Concurrent TTF with CRT patients were enrolled in a single-arm pilot study (clinicaltrials.gov Identifier: NCT03477110). For the comparison control of adjuvant TTF, adult patients with newly diagnosed GBM that had a KPS ≥ 60 who received treatment with CRT and adjuvant TMZ + TTF from three institutions were included. The adjuvant TTF cohort excluded patients who progressed during CRT or did not receive TMZ. PFS and OS were compared between groups. RESULTS A total of 87 patients were included in this study, of which 30 received concurrent TTF with CRT. Median patient age was 58 in the concurrent TTF group and 59 in the adjuvant TTF group. The median KPS in both groups was. MGMT methylation was present in 33.3% of the concurrent TTF and 32.0% in the adjuvant TTF group. 40% received GTR in the concurrent group and 38% received GTR in the adjuvant group. Multifocal disease was appreciated in 40% of patients in the concurrent TTF group. There was no significant difference in median OS (p=0.38) or PFS (p=0.76). CONCLUSIONS There was no difference in OS or PFS between concurrent or adjuvant TTF treatment groups. However, the adjuvant TTF group is expected to be a better prognosis due to the elimination of patients that progressed or declined after initial CRT. The current study suggested concurrent TTF treatment achieved outcomes to that of a better prognosis group. The survival benefit of concurrent TTF with CRT vs adjuvant TTF is being tested in the phase 3 TRIDENT EF-32 clinical trial (NCT04471844).
STEM-15. THERAPY-INDUCED CHANGES BY BRAF AND MEK INHIBITORS IN BRAF V600E-MUTATED GLIOMA MODELS PROVIDE POTENTIAL NOVEL THERAPEUTIC OPPORTUNITIES
Authors: Jongwhi Park, Hope Lancero, Emon Nasajpour, Cesar Garcia, Laura Prolo, Gerald Grant, Claudia Petritsch
Journal: Neuro-Oncology (2022)

Abstract Combinations of the MEK inhibitor trametinib, and BRAF inhibitor dabrafenib (BRAFi+MEKi) show rapid and sustained responses in patients with BRAF V600E-mutated low-grade glioma, but tumor rebound after treatment discontinuation is frequent. Moreover, a lack of response is common in patient with high-grade glioma raising the need for further research into BRAFi+MEKi effects on tumors. We showed previously that BRAF V600E-mutated glioma cells positive for CD133 (Prominin-1), a marker of brain tumor stem cells, show decreased sensitivity to BRAFi, indicative of their role in promoting therapy resistance. BRAF V600E-mutated murine and patient-derived glioma cell lines (STN-10049, SU-aGBM5) were generated and together with established BRAF V600E-mutated cell lines (DBTRG, AM38) were analyzed for changes in gene expression in response to 48 hrs treatment with BRAFi dabrafenib and MEKi trametinib. Cells were analyzed by RNA-seq and gene enrichment analyses while cell culture supernatant was analyzed for cytokine production using an ELISA. Syngeneic, orthotopic BRAF V600E-mutated tumor allograft-bearing mice were treated with BRAFi+MEKi, with therapeutic antibodies against immune checkpoint molecules (anti-PD-L1 and anti-CTLA-4) and with combination of all four agents, and tumors were analyzed by mass cytometry and immunofluorescence for stem and T cell markers. BRAFi+MEKi treatment induced an interferon gamma (IFNg) response gene signature in BRAF V600E-mutated glioma cells and increased HLA gene expression. The frequency of tumor-infiltrating CD4+ CD8+ T cells in syngeneic BRAF V600E-mutated tumor allografts increased with BRAFi+MEKi treatment. Combining BRAFi+MEKi with anti-PD-L1 and anti-CTLA-4 treatment decreased CD133+ cells more effectively than either therapy alone, and resulted in a T cell-dependent survival benefit of mice with orthotopic BRAF V600E-mutated high-grade glioma. Combination of BRAFi+MEKi with immune checkpoint inhibition should be further explored as a viable option to prevent tumor rebound and therapy resistance in patients with BRAF V600E-mutated glioma.